Karen L. King specializes in the history of early Christianity, the canonical gospels, and apocryphal writing. Her theoretical interests include orthodoxy and heresy, religion and gender, and violence and martyrdom, which have resulted in such books as The Secret Revelation of John (2006), The Gospel of Mary of Magdala: Jesus and the First Woman Apostle (2003), and What Is Gnosticism? (2003). She also coauthored Reading Judas: The Gospel of Judas and the Shaping of Christianity (2007) with Elaine Pagels.

In 2009 King was the first woman to be appointed Hollis Professor of Divinity at the Harvard Divinity School, the oldest endowed chair in the United States. Before that she had served for six years as Winn Professor of Ecclesiastical History at Harvard, where she has worked since 1997, and as professor of religious studies at Occidental College from 1984 to 1997.

King earned a PhD in history of religions from Brown University in 1984 and a BA in religious studies from the University of Montana in 1976. Her research has been supported by grants and fellowships from the Henry Luce Foundation, Norwegian Academy of Arts and Sciences, the Ford Foundation, and the National Endowment for the Humanities. In 2013 she won the Horace Mann Medal, awarded to a Brown Graduate School alumni for significant contributions to the recipient’s field.